In a gaseous fuel supply device disclosed in patent document 1, a filling route used for filling a fuel tank with gaseous fuel to be stored in the tank communicates with a fuel supply path used for supplying the fuel from the fuel tank to an injector. In this device, a fuel filling opening can communicate with the fuel tank through a solenoid valve and can communicate with the fuel tank through a first check valve. The solenoid valve and the first check valve meet each other in an upstream position near the fuel filling opening. The solenoid valve and the first check valve are connected to the fuel filling opening through a second check valve upstream from the solenoid valve and the first check valve. Patent document 1 recites that the first check valve is set at a valve opening pressure lower than that of the second check valve. The invention of patent document 1 places attention to a point that if the fuel tank is filled with the fuel from the fuel filling opening with the solenoid valve being kept closed while the respective valve opening pressures of the first and second check valves are in an inverse relationship, a fuel pressure in the fuel supply path rises and then drops and this pressure drop is sensed. Specifically, if the fuel pressure in the fuel supply path becomes the valve opening pressure of the first check valve or more during filling with the fuel, the first check valve is opened to drop the pressure in the fuel supply path once. Patent document 1 recites in paragraphs “0031” to “0034” that setting the first check valve at a valve opening pressure lower than that of the second check valve can prevent an announcement of a pressure drop in the fuel supply path from being issued during filling with the fuel.
Patent document 1 further recites in paragraph “0046” that a fuel-filled state is determined based on excess of a pressure in the fuel supply path over a predetermined value instead of setting a valve opening pressure, and then the actuation of a pressure sensor is stopped or an announcement is stopped.
The aforementioned phenomenon is not the only situation where an announcement is issued erroneously as a result of temporal drop in a fuel pressure during filling with the fuel. Even if the solenoid valve is kept opened during filling with the fuel, a pressure in the fuel supply path may still drop to the aforementioned level, while not dropping to a level targeted for an announcement. If the fuel-filled state is determined based on excess of a pressure in the fuel supply path over the predetermined value, an announcement may be issued erroneously or a period when an announcement stops may be extended more than necessary in a manner that depends on a way of setting a valve opening pressure.